锰对厚大断面球铁力学性能和断裂韧性的影响  

Influence of Manganese Concentration on Mechanical Properties and Fracture Toughness of Heavy Section Ductile Iron

作　　者：郭二军[1] 王丽萍[1] 宋良[2] 刘东戎[1] 

机构地区：[1]哈尔滨理工大学材料科学与工程学院,黑龙江哈尔滨150080 [2]黑龙江科技大学材料科学与工程学院,黑龙江哈尔滨150022

出　　处：《哈尔滨理工大学学报》2015年第6期1-8,共8页Journal of Harbin University of Science and Technology

基　　金：国家自然科学基金(51174068;51374086)

摘　　要：研究了锰对厚大断面球铁的力学性能及断裂韧性的影响.研究结果表明,锰含量的增加导致试块心部的珠光体含量相对较高,在一定程度上缓解了由石墨形态恶化所造成的抗拉强度下降.随着冷却凝固速度的降低和锰含量的增加,冲击断口形貌和断裂韧性断口形貌由韧-脆混合型断口裂转变为脆性断口.利用扫描电镜动态拉伸原位厚大断面球铁中不同基体组织的断裂过程,珠光体在外力作用下比铁素体容易萌生裂纹,裂纹往往沿着相邻的珠光体团交界扩展.珠光体的塑韧性较低且脆性大.厚大断面球铁中控制珠光体含量,提高铁素体含量,可提高球铁塑韧性.The effects of manganese（ Mn） concentration on the microstructures and mechanical properties and fracture toughness of heavy section ductile iron were investigated. Experimental results show that with increasing Mn concentration,the amount of pearlite is increased and the morphology of graphite is deteriorated. The elongation,impact toughness and fracture toughness obviously decrease with the increase of Mn. The decrease of tensile strength is not obvious due to the relatively high content of pearlite,which alleviates the decrease of tensile strength caused by the graphite morphology deterioration. The use of the in-situ scanning electronic microscope（ SEM） tensile experiment is to observe the dynamic tensile process,combined with the fracture analysis to study the effect of matrix（ pearlite and ferrite） on fracture process of heavy section ductile iron. Controlling the content of pearlite and increasing the amount of ferrite can improve the fracture toughness of the ductile iron.

关 键 词：厚大断面球铁 锰含量 冷却速度 原位拉伸 断裂韧性 

分 类 号：TG255[金属学及工艺—铸造]